Bilateral subthalamic nucleus stimulation improves health-related quality of life in PD

Cognitive Effects of Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease with GBA1 Pathogenic Variants

Genetic subtyping of patients with Parkinson's disease (PD) may assist in predicting the cognitive and motor outcomes of subthalamic deep brain stimulation (STN-DBS). Practical questions were recently raised with the emergence of new data regarding suboptimal cognitive outcomes after STN-DBS in individuals with PD associated with pathogenic variants in glucocerebrosidase gene (GBA1-PD). However, a variety of gaps and controversies remain. (1) Does STN-DBS truly accelerate cognitive deterioration in GBA1-PD? If so, what is the clinical significance of this acceleration? (2) How should the overall risk-to-benefit ratio of STN-DBS in GBA1-PD be established? (3) If STN-DBS has a negative effect on cognition in GBA1-PD, how can this effect be minimized? (4) Should PD patients be genetically tested before STN-DBS? (5) How should GBA1-PD patients considering STN-DBS be counseled? We aim to summarize the currently available relevant data and detail the gaps and controversies that exist pertaining to these questions. In the absence of evidence-based data, all authors strongly agree that clinicians should not categorically deny DBS to PD patients based solely on genotype (GBA1 status). We suggest that PD patients considering DBS may be offered genetic testing for GBA1, where available and feasible, so the potential risks and benefits of STN-DBS can be properly weighed by both the patient and clinician. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Stem Cell-based and Advanced Therapeutic Modalities for Parkinson's Disease: A Risk-effectiveness Patient-centered Analysis

Treatment of Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is currently considered a challenging issue since it causes substantial disability, poor quality of life, and mortality. Despite remarkable progress in advanced conventional therapeutic interventions, the global burden of the disease has nearly doubled, prompting us to assess the riskeffectiveness of different treatment modalities. Each protocol could be considered as the best alternative treatment depending on the patient's situation. Prescription of levodopa, the most effective available medicine for this disorder, has been associated with many complications, i.e., multiple episodes of "off-time" and treatment resistance. Other medications, which are typically used in combination with levodopa, may have several adverse effects as well. As a result, the therapies that are more in line with human physiology and make the least interference with other pathways are worth investigating. On the other hand, remaining and persistent symptoms after therapy and the lack of effective response to the conventional approaches have raised expectations towards innovative alternative approaches, such as stem cell-based therapy. It is critical to not overlook the unexplored side effects of innovative approaches due to the limited number of research. In this review, we aimed to compare the efficacy and risk of advanced therapies with innovative cell-based and stemcell- based modalities in PD patients. This paper recapitulated the underlying factors/conditions, which could lead us to more practical and established therapeutic outcomes with more advantages and few complications. It could be an initial step to reconsider the therapeutic blueprint for patients with Parkinson's disease.

Subthalamic and pallidal deep brain stimulation for Parkinson's disease-meta-analysis of outcomes

Although deep brain stimulation (DBS) of the globus pallidus internus (GPi) and the subthalamic nucleus (STN) has become an established treatment for Parkinson’s disease (PD), a recent meta-analysis of outcomes is lacking. To address this gap, we performed a meta-analysis of bilateral STN- and GPi-DBS studies published from 1990-08/2019. Studies with ≥10 subjects reporting Unified Parkinson’s Disease Rating Scale (UPDRS) III motor scores at baseline and 6–12 months follow-up were included. Several outcome variables were analyzed and adverse events (AE) were summarized. 39 STN studies (2035 subjects) and 5 GPi studies (292 subjects) were eligible. UPDRS-II score after surgery in the stimulation-ON/medication-OFF state compared to preoperative medication-OFF state improved by 47% with STN-DBS and 18.5% with GPi-DBS. UPDRS-III score improved by 50.5% with STN-DBS and 29.8% with GPi-DBS. STN-DBS improved dyskinesia by 64%, daily OFF time by 69.1%, and quality of life measured by PDQ-39 by 22.2%, while Levodopa Equivalent Daily Dose (LEDD) was reduced by 50.0%. For GPi-DBS information regarding dyskinesia, OFF time, PDQ-39 and LEDD was insufficient for further analysis. Correlation analysis showed that preoperative L-dopa responsiveness was highly predictive of the STN-DBS motor outcome across all studies. Most common surgery-related AE were infection (5.1%) and intracranial hemorrhage (3.1%). Despite a series of technological advances, outcomes of modern surgery are still comparable with those of the early days of DBS. Recent changes in target selection with a preference of GPi in elderly patients with cognitive deficits and more psychiatric comorbidities require more published data for validation.

Unraveling the Role of Astrocytes in Subthalamic Nucleus Deep Brain Stimulation in a Parkinson's Disease Rat Model

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective therapeutic strategy for motor symptoms of Parkinson's disease (PD) when L-DOPA therapy induces disabling side effects. Classical inflammatory activation of glial cells is well established in PD, contributing to the progressive neurodegenerative state; however, the role of DBS in regulating the inflammatory response remains largely unknown. To understand the involvement of astrocytes in the mechanisms of action of DBS, we evaluated the effect of STN-DBS in regulating motor symptoms, astrocyte reactivity, and cytokine expression in a 6-OHDA-induced PD rat model. To mimic in vivo DBS, we investigate the effect of high-frequency stimulation (HFS) in cultured astrocytes regulating cytokine induction and NF-κB activation. We found that STN-DBS improved motor impairment, induced astrocytic hyperplasia, and reversed increased IFN-γ and IL-10 levels in the globus pallidus (GP) of lesioned rats. Moreover, HFS activated astrocytes and prevented TNF-α-induced increase of monocyte chemoattractant protein-1 (MCP-1) and NF-κB activation in vitro. Our results indicate that DBS/HFS may act as a regulator of the inflammatory response in PD states, attenuating classical activation of astrocytes and cytokine induction, potentially through its ability to regulate NF-κB activation. These findings may help us understand the role of astrocyte signaling in HFS, highlighting its possible relationship with the effectiveness of DBS in neurodegenerative disorders.

Quality of life predicts outcome of deep brain stimulation in early Parkinson disease

Objective

To investigate predictors for improvement of disease-specific quality of life (QOL) after deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson disease (PD) with early motor complications.

Methods

We performed a secondary analysis of data from the previously published EARLYSTIM study, a prospective randomized trial comparing STN-DBS (n = 124) to best medical treatment (n = 127) after 2 years follow-up with disease-specific QOL (39-item Parkinson's Disease Questionnaire summary index [PDQ-39-SI]) as the primary endpoint. Linear regression analyses of the baseline characteristics age, disease duration, duration of motor complications, and disease severity measured at baseline with the Unified Parkinson’s Disease Rating Scale (UPDRS) (UPDRS-III “off” and “on” medications, UPDRS-IV) were conducted to determine predictors of change in PDQ-39-SI.

Results

PDQ-39-SI at baseline was correlated to the change in PDQ-39-SI after 24 months in both treatment groups (p < 0.05). The higher the baseline score (worse QOL) the larger the improvement in QOL after 24 months. No correlation was found for any of the other baseline characteristics analyzed in either treatment group.

Conclusion

Impaired QOL as subjectively evaluated by the patient is the most important predictor of benefit in patients with PD and early motor complications, fulfilling objective gold standard inclusion criteria for STN-DBS. Our results prompt systematically including evaluation of disease-specific QOL when selecting patients with PD for STN-DBS.

Clinicaltrials.gov identifier

NCT00354133.

[Effects of bilateral deep brain stimulation in the subthalamic nucleus using two methods of target structure verification]

AIM

To evaluate the efficacy of deep brain stimulation in the subthalamic nucleus (DBS STN) in patients with Parkinson's disease (PD) using different methods of targeting according to the dynamics of motor symptoms of PD.

MATERIAL AND METHODS

The study involved 90 patients treated with DBS STN. In 30 cases intraoperative microelectrode recording (MER) was used. MER was not performed in 30 patients of the comparison group. The control group consisted of 30 patients with PD who received conservative treatment. Hoehn and Yahr scale, Tinetti Balance and Mobility Scale (TBMS), Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Quality of Life-39 Scoring System (РDQ-39), Schwab & England ADL Scale were used. Levodopa equivalent daily dose (LEDD, 2010) was calculated for each patient.

RESULTS AND CONCLUSION

The effect of DBS STN using intraoperative microelectrode recording on the main motor symptoms, motor complications, walking as well as indicators of quality of life and daily activities was shown. In both DBS STN groups, there was a significant reduction in the LEDD and marked improvement of the control of motor symptoms of PD. A significant reduction in the severity of motor fluctuations (50%) and drug-induced dyskinesia (51%) was observed. Quality of life and daily activity in off-medication condition were significantly improved in both DBS STN groups of patients, irrespective of the method of target planning (75-100%), compared with the control group.

Functional correlates of the therapeutic and adverse effects evoked by thalamic stimulation for essential tremor

Thalamic deep brain stimulation (DBS) is an effective therapy for essential tremor. Gibson et al. use functional MRI to reveal patterns of activation that correlate with stimulation-induced therapeutic and adverse effects. Their results suggest that thalamic DBS controls tremor, and induces paraesthesias, through distal modulation of tremor-related network nodes.

Deep brain stimulation is an established neurosurgical therapy for movement disorders including essential tremor and Parkinson’s disease. While typically highly effective, deep brain stimulation can sometimes yield suboptimal therapeutic benefit and can cause adverse effects. In this study, we tested the hypothesis that intraoperative functional magnetic resonance imaging could be used to detect deep brain stimulation-evoked changes in functional and effective connectivity that would correlate with the therapeutic and adverse effects of stimulation. Ten patients receiving deep brain stimulation of the ventralis intermedius thalamic nucleus for essential tremor underwent functional magnetic resonance imaging during stimulation applied at a series of stimulation localizations, followed by evaluation of deep brain stimulation-evoked therapeutic and adverse effects. Correlations between the therapeutic effectiveness of deep brain stimulation (3 months postoperatively) and deep brain stimulation-evoked changes in functional and effective connectivity were assessed using region of interest-based correlation analysis and dynamic causal modelling, respectively. Further, we investigated whether brain regions might exist in which activation resulting from deep brain stimulation might correlate with the presence of paraesthesias, the most common deep brain stimulation-evoked adverse effect. Thalamic deep brain stimulation resulted in activation within established nodes of the tremor circuit: sensorimotor cortex, thalamus, contralateral cerebellar cortex and deep cerebellar nuclei (FDR q < 0.05). Stimulation-evoked activation in all these regions of interest, as well as activation within the supplementary motor area, brainstem, and inferior frontal gyrus, exhibited significant correlations with the long-term therapeutic effectiveness of deep brain stimulation (P < 0.05), with the strongest correlation (P < 0.001) observed within the contralateral cerebellum. Dynamic causal modelling revealed a correlation between therapeutic effectiveness and attenuated within-region inhibitory connectivity in cerebellum. Finally, specific subregions of sensorimotor cortex were identified in which deep brain stimulation-evoked activation correlated with the presence of unwanted paraesthesias. These results suggest that thalamic deep brain stimulation in tremor likely exerts its effects through modulation of both olivocerebellar and thalamocortical circuits. In addition, our findings indicate that deep brain stimulation-evoked functional activation maps obtained intraoperatively may contain predictive information pertaining to the therapeutic and adverse effects induced by deep brain stimulation.

Postoperative apathy can neutralise benefits in quality of life after subthalamic stimulation for Parkinson's disease

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) improves motor symptoms of Parkinson's disease, leading to improvement in health-related quality of life (HRQoL). However, an excessive decrease in dopaminergic medication can lead to a withdrawal syndrome with apathy as the predominant feature. The present study aims to assess the impact of postoperative apathy on HRQoL.

METHODS

A cohort of 88 patients who underwent STN-DBS was divided into two groups, those who were apathetic at 1 year and those who were not, as measured by the Starkstein scale. HRQoL was assessed using the Parkinson's disease questionnaire 39 (PDQ-39) and was compared between the two groups. We also compared activities of daily living, motor improvement and motor complications (Unified Parkinson's Disease Rating Scale, UPDRS), depression and anxiety, as well as cognition and drug dosages. Baseline characteristics and postoperative complications were recorded.

RESULTS

One year after surgery, 27.1% of patients suffered from apathy. While motor improvement was significant and equivalent in both the apathy (-40.4% of UPDRS motor score) and non-apathy groups (-48.6%), the PDQ-39 score did not improve in the apathy group (-5.5%; p=0.464), whereas it improved significantly (-36.7%; p≤0.001) in the non-apathy group. Change in apathy scores correlated significantly with change in HRQoL scores (r=0.278, p=0.009). Depression and anxiety scores remained unchanged from baseline in the apathy group (p=0.409, p=0.075), while they improved significantly in patients without apathy (p=0.006, p≤0.001). A significant correlation was found between changes in apathy and depression (r=0.594, p≤0.001).

CONCLUSIONS

The development of apathy after STN-DBS can cancel out the benefits of motor improvement in terms of HRQoL. Systematic evaluation and management of apathy occurring after subthalamic stimulation appears mandatory.

Deep brain stimulation in mental health: Review of evidence for clinical efficacy

OBJECTIVE

There is increasing interest in the use of deep brain stimulation as a treatment for psychiatric disorders. In this review, we consider the evidence for the effectiveness of deep brain stimulation for psychiatric indications, with a primary focus on obsessive compulsive disorder and major depressive disorder.

METHODS

Case reports, case series and clinical trials where deep brain stimulation was primarily utilised in the treatment of a psychiatric disorder, including obsessive compulsive disorder, major depressive disorder, anorexia nervosa or an addictive disorder were identified. The evidence for the effectiveness of deep brain stimulation in the treatment of obsessive compulsive disorder and major depressive disorder was reviewed with studies clustered by the site of implantation.

RESULTS

The majority of identified manuscripts report small case series or single cases. A limited number of studies have reported some form of randomised or blinded stimulation comparison. All of these comparative reports have included small samples of subjects (less than 20 per study in total) compromising the feasibility of making statistical comparison between outcomes in the comparison phases. The two exceptions to this have been industry-sponsored studies conducted in the treatment of major depressive disorder. However, both were stopped prematurely due to concerns about poor efficacy.

CONCLUSIONS

There is insufficient evidence at this point in time to support the use of deep brain stimulation as a clinical treatment for any psychiatric disorder outside of research and programmes where formal outcome data are being systematically collated. While some promising initial data exist to support its potential efficacy for a number of psychiatric conditions, further research is required to establish optimal implantation targets, patient characteristics associated with positive therapeutic outcomes and optimal deep brain stimulation parameters and parameter-programming methods.

[Current possibilities of quality of life improvement in the late stages of Parkinson's disease]

In this review, the authors describe the influence of Parkinson's disease on of the quality of life (QoL) of patients and highlight the importance of this parameter for assessment of treatment efficacy. Special attention is drawn to improvement of QoL in patients with resistant motor complications using invasive methods based on continuous dopaminergic stimulation. In the aspect of the influence on QoL, the main results of the studies of levodopa-carbidopa intestinal gel are reviewed.

Long-term outcome of subthalamic nucleus deep brain stimulation for Parkinson's disease using an MRI-guided and MRI-verified approach

BACKGROUND

Subthalamic nucleus (STN) deep brain stimulation (DBS) represents a well-established treatment for patients with advanced Parkinson's disease (PD) insufficiently controlled with medical therapies. This study presents the long-term outcomes of patients with PD treated with STN-DBS using an MRI-guided/MRI-verified approach without microelectrode recording.

METHODS

A cohort of 41 patients who underwent STN-DBS were followed for a minimum period of 5 years, with a subgroup of 12 patients being followed for 8-11 years. Motor status was evaluated using part III of the Unified Parkinson's Disease Rating Scale (UPDRS-III), in on- and off-medication/on-stimulation conditions. Preoperative and postoperative assessments further included activities of daily living (UPDRS-II), motor complications (UPDRS-IV), neuropsychological and speech assessments, as well as evaluation of quality of life. Active contacts localisation was calculated and compared with clinical outcomes.

RESULTS

STN-DBS significantly improved the off-medication UPDRS-III scores, compared with baseline. However, UPDRS scores increased over time after DBS. Dyskinesias, motor fluctuations and demands in dopaminergic medication remained significantly reduced in the long term. Conversely, UPDRS-III on-medication scores deteriorated at 5 and 8 years, mostly driven by axial and bradykinesia subscores. Quality of life, as well as depression and anxiety scores, did not significantly change at long-term follow-up compared with baseline. In our series, severe cognitive decline was observed in 17.1% and 16.7% of the patients at 5 and 8 years respectively.

CONCLUSIONS

Our data confirm that STN-DBS, using an MRI-guided/MRI-verified technique, remains an effective treatment for motor 'off' symptoms of PD in the long term with low morbidity.

Criteria for deep-brain stimulation in Parkinson’s disease: review and analysis

Deep-brain stimulation is currently the most effective surgical treatment for advanced Parkinson's disease. The relevant targets to date are the subthalamic nucleus and the globus pallidus internus, although the thalamus (ventralis intermedius nucleus) is preferred in tremor-dominant, aged Parkinson's disease patients. Long-term benefit in cardinal parkinsonian signs, motor fluctuations and dyskinesia has been reported in 5-year follow-up studies of subthalamic nucleus deep-brain stimulation. However, some psychiatric consequences have raised important issues and emphasized the need for an experienced deep-brain stimulation surgical team. This team should be multidisciplinary and involve movement disorder neurologists, neurosurgeons, neuropsychologists and psychiatrists. The recent observation that deep-brain stimulation of the pedunculopontine nucleus improves axial signs, possibly even in those less responsive to levodopa, brings new hope to the management of advanced Parkinson's disease.

Risks of common complications in deep brain stimulation surgery: management and avoidance

OBJECT

Deep brain stimulation (DBS) surgery is increasingly prominent in the treatment of various disorders refractory to medication. Despite the procedure's efficacy, the community at large continues to be hesitant about presumed associated risks. The main object of this study was to assess the incidence of various surgical complications occurring both during and after DBS device implantation in a large population of patients with movement disorders in an effort to better quantify patient risk, define management plans, and develop methods for risk avoidance. A second aim was to corroborate the low procedural complication risk of DBS reported by others, which in light of the procedure's efficacy is needed to promote its widespread acceptance.

METHODS

All patients who had undergone new DBS device implantation surgery between 2002 and 2010 by a single surgeon were entered into a database after being verified by cross-referencing manufacturer implantation records. All surgical records and charts were reviewed to identify intraoperative, perioperative, and long-term surgical complications, including any characteristics predictive of an adverse event.

RESULTS

Seven hundred twenty-eight patients received 1333 new DBS electrodes and 1218 new internal pulse generators (IPGs) in a total of 1356 stereotactic procedures for the treatment of movement disorders. Seventy-eight percent of the patients had staged lead and IPG implantations. Of the 728 patients, 452 suffered from medically refractory Parkinson disease; in the other patients, essential tremor (144), dystonia (64), mixed disease (30), and other hyperkinetic movement disorders (38) were diagnosed. Severe intraoperative adverse events included vasovagal response in 6 patients (0.8%), hypotension in 2 (0.3%), and seizure in 2 (0.3%). Postoperative imaging confirmed asymptomatic intracerebral hemorrhage (ICH) in 4 patients (0.5%), asymptomatic intraventricular hemorrhage in 25 (3.4%), symptomatic ICH in 8 (1.1%), and ischemic infarction in 3 (0.4%), associated with hemiparesis and/or decreased consciousness in 13 (1.7%). Long-term complications of DBS device implantation not requiring additional surgery included hardware discomfort in 8 patients (1.1%) and loss of desired effect in 10 (1.4%). Hardware-related complications requiring surgical revision included wound infections in 13 patients (1.7%), lead malposition and/or migration in 13 (1.7%), component fracture in 10 (1.4%), component malfunction in 4 (0.5%), and loss of effect in 19 (2.6%).

CONCLUSIONS

The authors confirmed that the overall risk of both procedure- and hardware-related adverse events is acceptably low. They offer advice on how to avoid the most common complications.

Neurosurgery in Parkinson's disease: Social adjustment, quality of life and coping strategies

Subthalamic nucleus deep brain stimulation has become a standard neurosurgical therapy for advanced Parkinson's disease. Subthalamic nucleus deep brain stimulation can dramatically improve the motor symptoms of carefully selected patients with this disease. Surprisingly, some specific dimensions of quality of life, “psychological” aspects and social adjustment do not always improve, and they could sometimes be even worse. Patients and their families should fully understand that subthalamic nucleus deep brain stimulation can alter the motor status and time is needed to readapt to their new postoperative state and lifestyles. This paper reviews the literatures regarding effects of bilateral subthalamic nucleus deep brain stimulation on social adjustment, quality of life and coping strategies in patients with Parkinson's disease. The findings may help to understand the psychosocial maladjustment and poor improvement in quality of life in some Parkinson's disease patients.

Lack of differential motor outcome with subthalamic nucleus region stimulation in Parkinson's disease

Deep brain stimulation (DBS) has emerged as a viable therapy for Parkinson's disease (PD). The impact of subthalamic nucleus (STN) lead placement (lateral versus medial) on motor outcome, however, has not been systematically evaluated. Forty-eight patients with PD underwent STN-DBS surgery and were evaluated postoperatively for 48 weeks for motor improvement as measured by the Unified Parkinson's Disease Rating Scale (UPDRS) part III (standardized motor examination) and levodopa equivalent daily dose (LEDD). Postoperative MRI was used to identify the location of the active stimulating contact and motor outcome was analyzed. STN-DBS was associated with significant improvement in motor outcome as determined by a reduction in the UPDRS part III subscore from 34.44 ± 1.29 at baseline to 18.76 ± 1.06 at end visit (p<0.0001) and a reduction in LEDD from 1721 ± 152 mg/day at baseline to 1134 ± 119 mg/day at end visit (p=0.0024). Patients with stimulating contacts in the medial STN compared to the lateral STN did not demonstrate any significant differences in motor outcome (UPDRS, p=0.5811; LEDD, p=0.7341). No significant differences were found in motor outcome between patients with STN stimulation compared to stimulation of surrounding fiber tracts (p=0.80). No significant difference in stimulation voltage was noted with respect to lead location. Our study did not find a significant effect for the location of active contact and motor outcome neither within the subregions of the STN nor between the STN and surrounding fibers. Further research is needed to better understand the neurophysiological basis for these results.

Moving forward: advances in the treatment of movement disorders with deep brain stimulation

The modern era of stereotactic and functional neurosurgery has ushered in state of the art technologies for the treatment of movement disorders, particularly Parkinson's disease (PD), tremor, and dystonia. After years of experience with various surgical therapies, the eventual shortcomings of both medical and surgical treatments, and several serendipitous discoveries, deep brain stimulation (DBS) has risen to the forefront as a highly effective, safe, and reversible treatment for these conditions. Idiopathic advanced PD can be treated with thalamic, globus pallidus internus (GPi), or subthalamic nucleus (STN) DBS. Thalamic DBS primarily relieves tremor while GPi and STN DBS alleviate a wide range of Parkinsonian symptoms. Thalamic DBS is also used in the treatment of other types of tremor, particularly essential tremor, with excellent results. Both primary and various types of secondary dystonia can be treated very effectively with GPi DBS. The variety of anatomical targets for these movement disorders is indicative of the network-level dysfunction mediating these movement disturbances. Despite an increasing understanding of the clinical benefits of DBS, little is known about how DBS can create such wide sweeping neuromodulatory effects. The key to improving this therapeutic modality and discovering new ways to treat these and other neurologic conditions lies in better understanding the intricacies of DBS. Here we review the history and pertinent clinical data for DBS treatment of PD, tremor, and dystonia. While multiple regions of the brain have been targeted for DBS in the treatment of these movement disorders, this review article focuses on those that are most commonly used in current clinical practice. Our search criteria for PubMed included combinations of the following terms: DBS, neuromodulation, movement disorders, PD, tremor, dystonia, and history. Dates were not restricted.

The emerging use of brain stimulation treatments for psychiatric disorders

OBJECTIVE

The aim of this study was to review the current state of development and application of a wide range of brain stimulation approaches in the treatment of psychiatric disorders.

METHOD

The approaches reviewed include forms of minimally invasive magnetic and electrical stimulation, seizure induction, implanted devices and several highly novel approaches in early development.

RESULTS

An extensive range of brain stimulation approaches are now being widely used in the treatment of patients with psychiatric disorders, or actively investigated for this use. Both vagal nerve stimulation (VNS) and repetitive transcranial magnetic stimulation (rTMS) have been introduced into clinical practice in some countries. A small body of research suggests that VNS has some potentially long-lasting antidepressant effects in a minority of patients treated. rTMS has now been extensively investigated for over 15 years, with a large body of research now supporting its antidepressant effects. Further rTMS research needs to focus on defining the most appropriate stimulation methods and exploring its longer term use in maintenance protocols. Very early data suggest that magnetic seizure therapy (MST) has promise in the treatment of patients referred for electroconvulsive therapy: MST appears to have fewer side effects and may have similar efficacy. A number of other approaches including surgical and alternative forms of electrical stimulation appear to alter brain activity in a promising manner, but are in need of evaluation in more substantive patient samples.

CONCLUSIONS

It appears likely that the range of psychiatric treatments available for patients will grow over the coming years to progressively include a number of novel brain stimulation techniques.

Functional imaging of subthalamic nucleus deep brain stimulation in Parkinson's disease

Deep brain stimulation of the subthalamic nucleus is an accepted treatment for the motor complications of Parkinson's disease. The therapeutic mechanism of action remains incompletely understood. Although the results of deep brain stimulation are similar to the results that can be obtained by lesional surgery, accumulating evidence from functional imaging and clinical neurophysiology suggests that the effects of subthalamic nucleus-deep brain stimulation are not simply the result of inhibition of subthalamic nucleus activity. Positron emission tomography/single-photon emission computed tomography has consistently demonstrated changes in cortical activation in response to subthalamic nucleus-deep brain stimulation. However, the technique has limited spatial and temporal resolution, and therefore the changes in activity of subcortical projection sites of the subthalamic nucleus (such as the globus pallidus, substantia nigra, and thalamus) are not as clear. Clarifying whether clinically relevant effects from subthalamic nucleus-deep brain stimulation in humans are mediated through inhibition or excitation of orthodromic or antidromic pathways (or both) would contribute to our understanding of the precise mechanism of action of deep brain stimulation and may allow improvements in safety and efficacy of the technique. In this review we discuss the published evidence from functional imaging studies of patients with subthalamic nucleus-deep brain stimulation to date, together with how these data inform the mechanism of action of deep brain stimulation.

Effects of subthalamic nucleus stimulation on emotional prosody comprehension in Parkinson's disease

BACKGROUND

Although impaired decoding of emotional prosody has frequently been associated with Parkinson's disease (PD), to date only few reports have sought to explore the effect of Parkinson's treatment on disturbances of prosody decoding. In particular, little is known about how surgical treatment approaches such as high frequency deep brain stimulation (DBS) affect emotional speech perception in patients with PD. Accordingly, the objective of this study was to evaluate the effect of subthalamic nucleus (STN) stimulation on prosody processing.

METHODOLOGY/PRINCIPAL FINDINGS

To this end the performance of 13 PD patients on three tasks requiring the decoding of emotional speech was assessed and subsequently compared to the performance of healthy control individuals. To delineate the effect of STN-DBS, all patients were tested with stimulators turned on as well as with stimulators turned off. Results revealed that irrespective of whether assessments were made "on" or "off" stimulation, patients' performance was less accurate as compared to healthy control participants on all tasks employed in this study. However, while accuracy appeared to be unaffected by stimulator status, a facilitation of reactions specific to highly conflicting emotional stimulus material (i.e. stimulus material presenting contradicting emotional messages on a verbal and non-verbal prosodic level) was observed during "on" stimulation assessments.

CONCLUSION

In sum, presented results suggest that the processing of emotional speech is indeed modulated by STN-DBS. Observed alterations might, on the one hand, reflect a more efficient processing of highly conflicting stimulus material following DBS. However, on the other hand, given the lack of an improvement in accuracy, increased impulsivity associated with STN stimulation needs to be taken into consideration.

High frequency deep brain stimulation of the subthalamic nucleus versus continuous subcutaneous apomorphine infusion therapy: a review

In advanced Parkinson's disease, several therapeutical option including not only lesional surgery (VIM, GPi) and deep brain stimulation (STN, GPi, VIM) but also continuous subcutaneous apomorphine infusion therapy can be proposed to the patient. The choice depends on the hope of the patient, patient's general health condition and the experience and choice of the neurosurgical and neurologist team. Here we report our experience based on 400 STN-DBS cases and we discuss, on the basis of our experience and on the literature, the advantage and disadvantage of DBS strategy as compared with non-surgical option such as continuous subcutaneous apomorphine infusion therapy.

Surgical and hardware complications of deep brain stimulation. A seven-year experience and review of the literature

PURPOSE

Deep brain stimulation (DBS) has been established as a safe and efficient method for the treatment of various movement disorders. As the emerging applications continue to expand and more centers become eligible for the procedure, complication rates and complication avoidance become increasingly important. Our aim was to report the DBS-related complication in our department over the last 7 years, compare our rates with those reported in the literature, and highlight those practices that will aid complications avoidance.

PATIENTS AND METHODS

Since 2003, 106 patients underwent DBS for various pathologies in our department. There were 38 (36%) females and 68 (64%) males with a mean age of 57 years. Preoperative diagnoses included Parkinson's disease (n = 88), dystonia (n = 12), tremor (n = 3), epilepsy (n = 1), obsessive-compulsive disorder (n = 1), and central pain syndrome (n = 1). Surgical and hardware-related complications, their treatment, and outcome were recorded and compared with those reported in the literature.

RESULTS

There were 12 procedure-related complications (11.3% of patients, 5.7% of the procedures). These included death (n = 1), aborted procedure (n = 1), postoperative respiratory distress (n = 3), intracranial hemorrhage (n = 2), epilepsy (n = 1), postoperative confusion or agitation (n = 3), and malignant neuroleptic syndrome (n = 1). Hardware-related complications presented in 4.3% of the procedures and included infection (five patients, 4.7%), electrode breakage (0.94%), lead migration or misplacement (0.94%), and stricture formation (two patients, 1.9%).

CONCLUSIONS

Complication rates after DBS surgery remain low, proving that DBS is not only effective but also safe. Certain strategies do exist in order to minimize complications.

Living with advanced Parkinson's disease: a constant struggle with unpredictability

AIM

This paper is a report of an exploration of patients' lifeworld and way of managing life with advanced Parkinson's disease prior to Deep Brain Stimulation and what they expect from life following this treatment.

BACKGROUND

Parkinson's disease is a progressive neurodegenerative disease, which is initially well-treated with L-dopa. Living with Parkinson's disease means living with the experience of continuous loss of independence and self-esteem and unpredictable ON/OFF phenomena. Thus, in the advanced stage of the disease, treatment with Deep Brain Stimulation may become relevant.

METHOD

Eleven patients eligible for Deep Brain Stimulation were interviewed prior to treatment. Data were collected in 2007 and analysed according to the hermeneutic phenomenological methodology of van Manen, using the four existentials as analytic tools.

FINDINGS

Living with advanced Parkinson's disease can be described as the experience of living with and managing unpredictability. The disease gradually took over, and participants had to struggle with unpredictability on a daily basis. Themes in relation to this were: The body - setting the agenda, Always a struggle to be on time, Living in dependence and compromise - being a burden, and Living with restrained space and changes in social life.

CONCLUSION

Parkinson's disease leads to profound bodily restrictions. Living with an unpredictable body affects all aspects of life, and nurses need to be aware of the impact the disease has on the entire lifeworld, and how this may affect the way treatment is perceived.

Effects of five years of chronic STN stimulation on muscle strength and movement speed

This study examined the long-term effects of chronic subthalamic nucleus (STN) deep brain stimulation (DBS) using both clinical evaluation and laboratory motor control measures. Over a 5-year time period, changes in the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) and movement speed and strength at the ankle joint were evaluated on and off STN DBS in eight patients with Parkinson's disease (PD). Four patients were also studied at the elbow joint. Patients with PD originally received unilateral STN DBS between years 2001 and 2003. They were re-evaluated after 5 years of long-term STN DBS between years 2006-2008. At baseline (year 0) and after 5 years, patients with PD were tested off treatment and on STN DBS. In each testing condition, patients performed ballistic, single degree of freedom ankle dorsiflexion and ankle plantarflexion movements and peak velocity was calculated. Patients also performed maximal voluntary contractions at the ankle joint in both directions, and peak torque was calculated. Results showed increased motor UPDRS scores from year 0 to year 5, but STN DBS was efficacious in reducing them. In contrast to the increase in motor UPDRS scores, motor control results showed a marked improvement in peak velocity and peak torque over the 5-year time period in the off treatment condition, and STN DBS was efficacious by improving both peak velocity and peak torque. The current findings suggest that 5 years of chronic STN DBS can have beneficial effects on the motor system over the long term in discrete motor tasks in which maximal effort and maximal neural output is required.

Deep brain stimulation state of the art and novel stimulation targets

Levodopa therapy represents a major breakthrough in the treatment of Parkinson's disease (PD). As time and disease severity progresses, however, the shortcomings and adverse effects of this neurotransmitter replacement strategy become apparent and patients develop disabilities despite best medical therapy. The heightened awareness of these difficulties has given birth to a re-examination of functional neurosurgery for advanced PD. In the 20 years since the renewed interest in deep brain stimulation (DBS), approximately 60,000 patients with PD have undergone this surgery, with an annual accrual of 8000-10,000 new patients per year worldwide. Clinical studies have confirmed the beneficial effects of DBS surgery for the treatment of the cardinal motor features of PD. The likelihood of improvement, however, varies from symptom to symptom and from patient to patient. Surgery is very effective in reducing the motor fluctuations and dyskinesias--the primary reasons for patients' intolerance to medical therapy. Other problems are less or non-responsive. Further, despite the widespread use of this technology, the mechanism through which DBS alleviates symptoms is not fully understood. This review will discuss the patient population most likely to benefit from surgery, what aspects of the disease are most responsive, the current limitations of DBS, and new therapeutic targets that are being examined to address these limitations.

Deep brain stimulation of the subthalamic nucleus in Parkinson's Disease 1993 – 2003: where are we 10 years on?

Since its advent in 1993, high frequency stimulation (HFS) of the subthalamic nucleus (STN) has rapidly developed into the most commonly practiced surgical procedure for the treatment of Parkinson's Disease (PD). Although its exact mechanism of action, be it through an inhibitory depolarization block, desynchronization of neuronal circuits or other means, is not clear, the efficacy and safety of the technique are now well established. HFS of the STN improves the motor function by at least 60%, drastically reduces the levodopa requirement and significantly improves the quality of life in PD. This review updates the recent concepts on the pathophysiology of PD and analyses the basic science principles underlying the clinical practice of the STN HFS. The evolution of the surgical technique and long-term patients' outcome are further discussed.

Deep brain stimulation of the subthalamic nucleus for the treatment of Parkinson's disease

High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN-HFS) is the preferred surgical treatment for advanced Parkinson's disease. In the 15 years since its introduction into clinical practice, many studies have reported on its benefits, drawbacks, and insufficiencies. Despite limited evidence-based data, STN-HFS has been shown to be surgically safe, and improvements in dopaminergic drug-sensitive symptoms and reductions in subsequent drug dose and dyskinesias are well documented. However, the procedure is associated with adverse effects, mainly neurocognitive, and with side-effects created by spread of stimulation to surrounding structures, depending on the precise location of electrodes. Quality of life improves substantially, inducing sudden global changes in patients' lives, often requiring societal readaptation. STN-HFS is a powerful method that is currently unchallenged in the management of Parkinson's disease, but its long-term effects must be thoroughly assessed. Further improvements, through basic research and methodological innovations, should make it applicable to earlier stages of the disease and increase its availability to patients in developing countries.

Cerebral implants and Parkinson's disease: a unique form of biographical disruption?

Chronic illness is perceived as a particular kind of event. The aim of this paper is to understand the personal, familial and professional difficulties experienced by patients in France who have a neurodegenerative disease and undergo cerebral implants. This paper is based on the assumption that a treatment using biotechnical techniques is a unique disruptive experience which redefines the patient's life. Thirty patients (13 women and 17 men) from two French hospitals were interviewed at different stages of their medical history. Despite the excellent overall outcome of neurosurgery in patients with Parkinson's disease, there is often a contrast between the improvement in motor disability and the patient's difficulty in returning to normal life. These results allow us to analyse the link between the neurosciences and the experience of chronic illness.

Brain stimulation techniques for the treatment of depression and other psychiatric disorders

OBJECTIVE

The aim of this paper was to review the development of repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST), vagal nerve stimulation (VNS), deep brain stimulation (DBS) and other recent brain stimulation techniques for their potential use in the treatment of a range of psychiatric disorders.

CONCLUSIONS

A considerable number of studies have been conducted to investigate the efficacy of rTMS. Although there are considerable problems with this research base, globally the studies suggest that rTMS has antidepressant efficacy. However, more research is required to define the most effective way of applying this technique. There is a much smaller research base supporting the use of VNS and to date the research suggests that only a minority of patients benefit from this procedure. Considerably more research is required in the use of the other techniques which at this stage have been tested only to a very small degree. It is likely that one, and possibly a number, of the new brain stimulation techniques will become available clinically in the psychiatric armamentarium in the coming years. However, considerable research is still required to establish efficacy and define the appropriate place in clinical practice for these treatment approaches.

Deep brain stimulation for Parkinson's disease

The surgical treatment of Parkinson's disease has been through a revival phase over the last 20 years with the development of deep brain stimulation (DBS). Thalamic DBS was developed first and has proven to be a very effective treatment for tremor. The limitation is the lack of effect on other symptoms. Other targets were therefore investigated, and the procedure was applied to the subthalamic nucleus (STN) and the internal globus pallidus (GPi). STN stimulation can improve a wide range of symptoms and is currently the preferred target for many patients. Nevertheless, the morbidity seems higher than with other targets, and the selection criteria have to be quite strict. When STN DBS is not advised, thalamic DBS remains an option for patients with severe tremor, and GPi stimulation for those with severe dyskinesias. DBS remains a symptomatic treatment for a limited number of patients; it does not seem to alter the disease progression, and many patients are not suitable. There is, therefore, the need for further research into other targets and other approaches.

Globus pallidus stimulation improves both motor and nonmotor aspects of quality of life in advanced Parkinson's disease

Our purpose was to measure the change in quality of life (QoL) following deep brain stimulation of the globus pallidus interna (GPi-DBS) in advanced Parkinson 's disease (PD), and identifies any associations with changes in motor features of the disease. Eleven patients (age range 54-69 years, 2 women) underwent GPi-DBS (4 unilateral, 7 bilateral). Outcome measures included assessment of PD-specific QoL (mean 8 months postsurgery) using the PDQ-39 questionnaire, and standard motor assessments. Off-period UPDRS III motor scores fell by (43 +/- 8)% (mean +/- SEM). Dyskinesia severity was reduced on the abnormal involuntary movement scale by (80 +/- 3)% and UPDRS IVa by (58 +/- 8)%. QoL as assessed by the PDQ39SI improved by (30 +/- 5)%, with significant improvements in mobility, activities of daily living, bodily discomfort, emotional wellbeing, communication, and cognitions subscales. Bilateral and unilateral groups demonstrated equivalent PDQ39SI improvement. QoL improvement was highly correlated with dyskinesia reduction but not reduction in UPDRS score or age at surgery. GPi-DBS markedly improves QoL in advanced PD. The impacts are broad and improve QoL domains not directly affected by the motor symptoms of the disease. Reduced dyskinesia plays a major role in the improvement of QoL in GPi-DBS treated patients.

Deep brain stimulation of CM/PF of thalamus could be the new elective target for tremor in advanced Parkinson's Disease?

Aim of this study was to investigate whether Deep Brain Stimulation (DBS) of the Centre Median Nucleus/Parafascicular (CM/PF) Complex is useful in reducing extrapyramidal symptoms in advanced Parkinson's Disease (PD) patients. In particular, we compared the action of CM/PF and subthalamic nucleus (STN) DBS on resting hand tremor using EMG surface of ulnar and radial right-hand muscles. Our results show that C/M DBS is very effective in reducing tremor, indicating this complex as a new target in advanced PD patients.

Update on surgery for Parkinson's disease

PURPOSE OF REVIEW

The clinical effectiveness and limitations of subthalamic nucleus deep brain stimulation for Parkinson's disease are summarized and recent developments concerning alternative brain targets for deep brain stimulation or restorative surgical therapies are discussed.

RECENT FINDINGS

In a controlled study subthalamic nucleus deep brain stimulation was superior to best medical management in improving quality of life of patients with advanced Parkinson's disease. The benefits of the procedure on levodopa-sensitive motor symptoms are sustained for up to 5 years, but it does not halt disease progression. Cognitive decline and worsening of axial motor symptoms may limit the overall benefit. Age at the time of surgery is an important factor for long-term stability and safety. Psychosocial aspects of Parkinson's disease can profoundly impact on the ability of a patient to reintegrate after surgery and have to be considered in patient selection. Stimulation of the pedunculopontine nucleus may have an additive effect on postural and gait symptoms, which do not respond to levodopa or subthalamic nucleus deep brain stimulation.

SUMMARY

Deep brain stimulation is emerging from an empirical to an evidence based therapy. The safety and efficacy of the procedure may legitimize surgery at a younger age before social maladjustment prevents reintegration of the patient into a normal life.

Surgical and hardware complications in subthalamic nucleus deep brain stimulation

OBJECTIVE

To assess the surgical and hardware complications in 26 consecutive patients with movement disorders undergoing subthalamic deep brain stimulation (STN-DBS) in early practice at our institute.

METHODS

The 26 patients in our institute were analyzed retrospectively. Group A included the first eight patients treated while we had no facility for microelectrode recording (MER), 16 intracranial procedures were performed and 8 batteries were implanted. Group B (with MER) included 18 patients, 35 intracranial procedures were performed and 18 batteries were implanted.

RESULTS

The intracranial morbidity was 18.75% in group A and 5.71% in group B. The extracranial morbidity was 37.5% in group A and 16.67% in group B. There was no hardware-related infection in our study. The overall mortality rate was 7.69%, and deaths were not surgical related.

CONCLUSIONS

The associated morbidity is significant in STN-DBS. The use of MER may improve the clinical outcome while decreasing the morbidity.